let typeWriter = document.getElementsByClassName('typeWriter')[0];
typeWriter.setAttribute('data-text',
    '["System.out.println(\\"Hello,World!\\");", ' +
    '"printf(\\"Hello,World!\\");", ' +
    '"std::cout << \\"Hello,World!\\" << std::endl;", ' +
    '"print(\\"Hello,World!\\")", ' +
    '"Console.WriteLine(\\"Hello,World!\\");", ' +
    '"echo \\"Hello,World!\\";", ' +
    '"console.log(\\"Hello,World!\\")"]')

let introduction = document.getElementById('index');
introduction.setAttribute('class', introduction.getAttribute('class') + ' active');